The influence of thermal treatment on the performance of Ni/Al2O3 catalyst

The data showing the influence of calcination conditions on physical and catalytic properties of Ni/Al2O3 catalyst, are presented and discussed. The catalyst characterization was performed by X-ray diffraction analysis and adsorption of nitrogen at 77 K. Activity of the Ni/Al2O3 catalyst was tested using benzene hydrogenation in the presence of thiophene as poisoning molecule. It has been found that the calcination temperature directly influenced physico-chemical properties responsible for thioresistance of Ni/Al2O3 catalyst, whereas calcination time had little effect on the catalytic properties of catalyst. The crystallite size of NiO and of the support particles increased with the elevation of calcination temperature from 573 to 873 K, while the surface area of the catalyst decreased. Benzene conversion was higher, and the catalyst deactivation due to thiophene poisoning, was slower, when the crystallites were smaller. That indicated, that both reaction, i.e. benzene hydrogenation and catalyst poisoning by thiophene, were structure-sensitive and that calcination at 873 K probably led to modification of electronic properties of the catalytic active sites. At the same time, higher resistance to thiophene poisoning may prolong the catalyst lifetime.